Moorella bacteria, which are industrially advantageous in producing acetic acid and ethanol from a gas, are expected to show improvement in production efficiency for e.g. ethanol.
Inventors of the present invention examined introduction of a useful function such as improvement in production efficiency for ethanol by transforming Moorella bacteria. However, since Moorella bacteria are genetically specific unlike other types of bacteria and have not been fully identified in property, it is, in fact, technologically difficult to transform Moorella bacteria. In cases where a mutation treatment is performed on Moorella bacteria with a chemical substance such as nitrosoguanidine (NTG), a strain that can maintain ethanol production in large volumes even after several passages cannot be obtained, or a transformation-confirmed strain was not obtained when a plasmid vector as an extrachromosomal gene was attempted to be introduced.
Inventors of the present invention have experimentally succeeded in obtaining uracil-requiring Moorella bacteria by destroying a gene coding for orotate phosphoribosyltransferase (pyrE) as an enzyme associated with a uracil biosynthetic system by homologous recombination by using a Moorella sp. HUC22-1 strain (Moorella bacteria) as a basal strain (Patent Document 1).
However, since the uracil-requiring Moorella bacteria had a difficulty in completing complementary sequence by incorporating a pyrE again, a specific method for expressing a transforming-gene by introducing the transforming-gene was unsuccessfully established.